U.S. patent application number 14/353336 was filed with the patent office on 2014-09-25 for ground covering for sports areas, and method for producing it.
This patent application is currently assigned to Sportek OHG. The applicant listed for this patent is Sportek OHG. Invention is credited to Hans-Joachim Schneider.
Application Number | 20140287844 14/353336 |
Document ID | / |
Family ID | 47227778 |
Filed Date | 2014-09-25 |
United States Patent
Application |
20140287844 |
Kind Code |
A1 |
Schneider; Hans-Joachim |
September 25, 2014 |
GROUND COVERING FOR SPORTS AREAS, AND METHOD FOR PRODUCING IT
Abstract
A ground covering for sports areas, in particular tennis courts.
In order to provide a ground covering for sports areas and in
particular for tennis courts which has not only the advantageous
play properties of a sand court but also the care and maintenance
properties of a hard court, there is provided at least one layer
(4) having a first, mineral particle material (1) which is doubly
crushed and a second particle material (3) and also a binder (2),
wherein an average particle size of the second material (3) is less
than an average particle size of the first material (1), and the
second material (3) is arranged at least partially in depot zones
(5) formed by the first material.
Inventors: |
Schneider; Hans-Joachim;
(Olfen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sportek OHG |
Olfen |
|
DE |
|
|
Assignee: |
Sportek OHG
Olfen
DE
|
Family ID: |
47227778 |
Appl. No.: |
14/353336 |
Filed: |
November 9, 2012 |
PCT Filed: |
November 9, 2012 |
PCT NO: |
PCT/EP2012/072256 |
371 Date: |
April 22, 2014 |
Current U.S.
Class: |
472/92 |
Current CPC
Class: |
E01C 13/065
20130101 |
Class at
Publication: |
472/92 |
International
Class: |
E01C 13/06 20060101
E01C013/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2011 |
DE |
10 2011 055 235.9 |
Claims
1-11. (canceled)
12. A ground covering for sports areas, in particular tennis
courts, at least having one layer (4) with a first mineral particle
material (1), a second particle material (3) as well as a binder
(2), wherein an average particle size of the second material (3) is
less than an average particle size of the first material (1), the
first material (1) is bound by the binder (2) and the second
material (3) is arranged at least partially in depot zones (5)
formed by the first particle material (1), wherein the second
particle material (3) comprises an elastic granulate.
13. The ground covering according to claim 12, wherein the first
particle material (1) is a crushed mineral particle material
(1).
14. The ground covering according to claim 12, wherein furthermore
a subset of the second material (3) is bound by the binder (2).
15. The ground covering according to claim 12, wherein the average
particle size of the second particle material (3) is between 0.1-5
mm.
16. The ground covering according to claim 15, wherein the average
particle size of the second particle material (3) is 0.1-1.5
mm.
17. The ground covering according to claim 12, wherein the binder
(2) comprises at least one water-impermeable polymer.
18. The ground covering according to claim 12, wherein the binder
(2) is a polyurethane binder.
19. The ground covering according to claim 12, wherein the second
particle material (3) is an elastic granulate, the elastic
granulate being selected from the group consisting of ethylene
propylene diene rubber and styrene butadiene rubber and a mixture
of ethylene propylene diene rubber and styrene butadiene
rubber.
20. The ground covering according to claim 12, wherein a
predominant part of the second particle material (3) is included in
the depot zones (5).
21. The ground covering according to claim 12, wherein the layer
(4) is a play layer.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a ground covering for sports areas
and in particular for tennis courts and a method for producing a
corresponding ground covering.
[0002] Coverings for sports areas and in particular also for tennis
courts are known in the state of the art. Normally, ground
coverings for tennis courts specifically are divided into two basic
categories, namely hard courts on one hand and sand or respectively
brick dust courts on the other hand, wherein the latter are also
called "clay courts".
[0003] Hard courts have relatively good play properties, namely a
consistent ball bounce and a high ball speed. Moreover, hard courts
require little maintenance and no watering. Conventional hard
courts are disadvantageous due to their relatively high
construction costs, the high ball and shoe abrasion, a high ball
bounce as well as a high stress on the ligaments, tendons and
joints of the athletes or respectively players due to the blunt and
hard surface.
[0004] In the contrast, the advantages of sand courts are low
construction costs, a low ball speed, longer ball exchanges, good
dampening properties as well as advantageous turning and sliding
properties of the athletes or respectively players. The
disadvantages of sand courts are the comparatively higher
maintenance, only low freeze resistance, the need to be constantly
watered as well as inconsistent ball bounce.
[0005] Due to the described advantages and disadvantages, it was
already attempted in the state of the art to reproduce the play and
slide behavior of a sand court tennis covering in the case of
simultaneously improved maintenance properties.
[0006] Thus, e.g. EP 0 358 209 A2 discloses a tennis court covering
with a first layer made of an elastic polymer material and a second
layer made of hard sand reinforced with a binder. A non-reinforced
brick dust layer is provided as the sliding layer.
[0007] However, this type of covering is problematic due to the
permanent grating of the scattered sliding layer so that a high
abrasion and thus wear of the covering results. Besides the need
for frequent maintenance due to the wear, the water permeability
through the sliding material crushed in this manner also decreases
greatly even after a short period of play. The covering becomes
hereby mainly water-impermeable, which greatly impairs controlled
start and stop movements by the athletes or respectively players as
well as the sliding properties of the covering specifically needed
in tennis. Thus, in the case of this type of covering, the play
properties are considerably degraded even after a short period of
play.
SUMMARY OF THE INVENTION
[0008] Based on the aforementioned problems, the object is to
provide a ground covering for sports areas and in particular for
tennis courts, which has on one hand the advantageous play
properties of a sand court but improved care and maintenance
properties.
[0009] The object is solved through a ground covering for sports
areas and in particular for tennis courts as disclosed herein as
well as a corresponding method for producing a ground covering as
disclosed herein. The disclosure also describes preferred
embodiments of the invention.
[0010] According to the invention, the ground covering has at least
one layer with a first mineral particle material, a second particle
material and a binder. An average particle size of the second
particle material is less than an average particle size of the
first particle material. The first particle material is bound with
the binder. According to the invention, the first mineral particle
material is crushed multiple times.
[0011] The ground covering according to the invention thus has at
least one layer with two particle materials, which have different
average particle sizes. The first mineral particle material hereby
forms an open porous frame due to the larger particle size, so that
the second particle material is arranged at least partially in the
gaps formed by the frame--hereinafter referred to as "depot
zones."
[0012] In the context of the present invention, the term "particle
material" means a (solid) substance that consists mainly of a
plurality of individual particles or respectively grains and is
also called particulate or respectively granulate medium.
[0013] According to the invention, the first particle material is
bound by the binder, i.e. the individual particles of the first
material adhere together in the layer of the covering and thus form
a film-like composite. Naturally, it is hereby neither required
that each grain of the first particle material is correspondingly
bound nor that it is a completely "rigid" composite. As explained
below, it is rather preferred when the binder also has a certain
elasticity in the hardened state.
[0014] The mineral, first particle material crushed multiple times
forms an open porous frame, which results in an advantageously
stabile structure of the ground covering. Due to the plurality of
smaller connection or respectively adhesion zones on the individual
particles, the ground covering according to the invention has
advantageous properties similar to a hard court, namely a certain
surface elasticity, which ensures an advantageous ball bounce.
Furthermore, the binder ensures that the water absorption of the
particles of the mineral first particle material is limited, which
increases freeze resistance. The covering is thereby particularly
durable since hardly any wear occurs on the covering.
[0015] The invention combines the advantageous properties of a hard
court with those of a clay court. The covering only needs little
maintenance and can be installed on any existing subsurface.
Moreover, the covering enables controlled sliding, wherein a
consistent ball bounce and a medium ball speed are achieved.
[0016] Due to the structure with first and second particle
material, the covering is furthermore "combination elastic", which
involves critical advantages with respect to pressure load and has
a gentler impact on joints.
[0017] Thus, for example in the case of an adult athlete weighing
approx. 70-90 kg, the coarse-grained, first particle material
ensures an extensive dissipation of force during running or jumping
due to the mentioned surface elasticity. In contrast, in the case
of an athlete, e.g. a child weighing approx. 30-40 kg, the second
particle material contained in the depot zones exerts a
spot-elastic function. This ensures protection of the ligaments,
tendons and joints and of the back musculature in the case of
different pressure loads.
[0018] Furthermore, the covering is mainly wear-proof since very
little wear occurs due to the material combination.
[0019] The second particle material can have any suitable design,
wherein however the average particle size of the second particle
material is less than the average particle size of the first
particle material so that the second particle material can at least
partially fill the depot zones resulting from the first
material.
[0020] As already discussed initially, the first particle material
is a mineral and is crushed multiple times. All suitable mineral
substances that are available in particle form, e.g. as a granular
mixture or granulate, are hereby considered. Within the framework
of the present invention, "mineral" materials are all minerals,
such as in particular granite, basalt, quartz and in particular
clay minerals, but also processed substances, such as ceramic, ash,
slag, slate chippings or threshing material.
[0021] In the same manner, the second particle material can
comprise a suitable granular mixture or granulate.
[0022] According to the invention, at least the first particle
material is bound with the binder. The binder can hereby be a
natural and/or synthetic binder. For example, a suitable binder can
comprise a cement and/or a polymer material and, in the latter
case, e.g. epoxide resins and/or polyacrylates, in particular
polymethacrylate. The binder is preferably weather-resistant and/or
water-impermeable.
[0023] The shape of the individual particles of the first and
second particle material is not restricted further. However, the
first mineral particle material is a mineral material that has been
doubly crushed or respectively crushed multiple times, i.e. a
mineral substance that has been artificially reduced in size. This
results in a mainly cubic shape of the particles, whereby the
binding in the layer and the formation of sufficiently large depot
zones is improved. Naturally, the first particle material can have
a smaller portion of particles that have not been crushed multiple
times.
[0024] Advantageously, the first particle material has
high-quality, doubly crushed chippings and in particular clay
granulate.
[0025] According to a preferred further development of the
invention, the second particle material is also a mineral material,
wherein particularly preferably the second particle material
comprises quartz powder and/or burned clay. This results in even
more improved durability properties of the covering.
[0026] Alternatively or additionally, the second particle material
has an elastic granulate. The second particle material can hereby
comprise a portion of elastic granulate, e.g. in a mixture with a
mineral material. Alternatively, the second particle material can
be completely designed as an elastic granulate.
[0027] The granulate can be synthetic or naturally produced. The
elastic granulate is preferably made of ethylene propylene diene
rubber (EPDM=ethylene propylene diene monomer) and/or styrene
butadiene rubber (SBR).
[0028] The ground covering according to the invention or
respectively the at least one layer can comprise first and second
particle material in any mixture ratio, namely according to the
desired properties, in particular with respect to elasticity and
ball speed.
[0029] The layer preferably has a thickness between 15-50 mm and
preferably 25 mm, i.e. the particle materials are applied in an
appropriate quantity. After the application of the first particle
material and before application of the second particle material,
the first particle material should preferably be stripped or
respectively polished with a suitable device.
[0030] Advantageously, the layer formed in this manner has a
portion of gaps or respectively depot zones of 10-60% and in
particular 40% by volume, which, as initially described, are at
least partially filled in by the second material in the finished
covering.
[0031] The quantity of the second particle material can preferably
be selected so that a predominant part and in particular at least
75% and especially at least 80% of the second particle material is
received in the gaps or respectively depot zones, i.e. the second
particle material is applied "in excess".
[0032] The corresponding low excess of the applied second particle
material remains on the surface. This permits even more improved
sliding or respectively controlled braking. Due to the low excess
present on the surface and the mainly unbound particles, a "chock"
forms in front of the shoe of the player in the case of sudden
stopping movements, which presses against the edges of the depot
zones with a high pressure. An even more improved control over the
movement progression is thus advantageously enabled.
[0033] According to a further development of the invention, a
subset of the second material is also bound by the binder. That is,
the grains or respectively particles of the subset are contained in
the more or less solid composite made up of the first particle
material and binder. A corresponding covering can be obtained e.g.
in that the second particle material is applied during the setting
time of the binder, i.e. at a time when the binder is still
partially liquid and not completely set.
[0034] The present preferred embodiment of the ground covering
according to the invention permits a selection of the elasticity of
the covering depending on the use and desired application. In the
case of the present preferred further development, the subset
described above is combined with the binder and the first particle
material, i.e. the individual grains or respectively particles of
the subset stabilize the composite made up of the first particle
material and binder. The elasticity of the covering is
correspondingly reduced. The respectively bound subset can be set
through corresponding selection of the setting time before
application of the second particle material. The further along the
setting of the binder during the application, the smaller the bound
subset in the later finished covering and the higher its
elasticity. The subset in relation to the second particle material
is preferably between 1-10%.
[0035] As already explained initially, the first particle material
and the second particle material can have all suitable embodiments,
particle shapes and particle sizes as long as the average particle
size of the second particle material is less than the average
particle size of the first particle material.
[0036] Advantageously, the average particle size of the first
particle material is between 3-20 mm, preferably between 4-10 mm
and particularly preferably between 6-10 mm. The average particle
size of the second particle material can be alternatively or
additionally preferably between 0.1-5 mm, particularly preferably
between 0.1-1.5 mm and advantageously between 0.5-1.2 mm. The use
of the second particle material described above without zero
portions is advantageous in particular because a corresponding
covering does not require watering and can thus be used inside
(e.g. in tennis centers) as well as outside year-round in all
climate zones.
[0037] According to a preferred further development of the
invention, the second particle material is applied in a quantity of
0.8-4 kg/m.sup.2 and in particular 1.5 kg/m.sup.2, which has proven
to be advantageous in particular in the case of the initially named
particle size.
[0038] As already discussed initially, the binder can be a natural
and/or synthetic binder. According to a preferred further
development of the invention, the binder has at least one
water-impermeable polymer material.
[0039] Advantageously, the binder is a polyurethane binder.
[0040] The binder can hereby be made of e.g. polyurethane-forming
prepolymers or can contain already (partially) prepolymerized
polyurethane. The polyurethane binder has particularly preferably a
(single-component) PUR diphenylmethane diisocyanate. This type of
material hardens by reaction with moisture under formation of
CO.sub.2 into a solid, elastic and insoluble film, which is also
film-like and thus water-impermeable. Accordingly, the particles of
the first and, if applicable, the subset of the second particle
material are mainly encased in a thin PUR film. Naturally, it is
possible that the binder also comprises further components in this
case, such as e.g. further polymer components and/or curing
agents.
[0041] The portion of the binder in relation to the quantity of the
first particle material should be selected in a suitable
manner.
[0042] Advantageously, the portion of binder is between 3-13%,
preferably 7%. Particularly preferably, the binder has a viscosity
of approx. 8000 mPa*s to 3000 mPa*s and more preferably 4500 mPA*s
depending on the temperature, in order to minimize or respectively
to avoid a tempering of the binder on the individual particles at
higher temperatures above 20.degree. C.
[0043] Advantageously, the at least one previously mentioned layer
of the ground covering is a play layer, i.e. the type of layer that
closes the ground structure towards the top and is thus in direct
contact with the players or respectively the sports equipment.
[0044] According to the invention, it thus concerns an elastic
sliding covering for sports areas.
[0045] Another aspect of the present invention relates to a method
for producing a ground covering for sports areas and in particular
tennis courts.
[0046] According to the invention, a first particle material is
hereby mixed with a binder in a first step. The particle material
provided with the binder is then applied to at least one part of
the sports area as long as the binder is still liquid or
respectively has not hardened completely. A second particle
material is then applied to at least part of the sports area. An
average particle size of the second particle material is hereby
less than an average particle size of the first particle
material.
[0047] The aforesaid method permits the creation of a ground
covering or respectively a layer according to the aforementioned
aspect of the present invention, in that the first particle
material is bound by the binder and forms an open porous frame so
that the second particle material is arranged at least partially in
the gaps or respectively "depot zones" formed by the frame.
[0048] The mentioned mixing can hereby take place using a suitable
mixing device and in particular a compulsory mixer in order to
obtain a homogeneous mixture of the first particle material and the
binder. In the context of this explanation, a homogeneous mixture
is understood in that the individual particles of the first
particle material are mainly surrounded by a thin film of the
binder.
[0049] The application of the first particle material mixed with
the binder can take place e.g. in a sprinkled application. The
first particle material is then preferably stripped or respectively
polished with a suitable device, whereby the open porous frame with
depot zones described above is formed.
[0050] The porosity or respectively size and number of depot zones
is hereby dependent on the particle size and particle shape and on
the stripping speed of the stripping procedure. Thus, in the case
of an increased stripping speed, the size of the depot zones can be
increased since the individual particles or respectively grains of
the first particle material are hereby pulled further apart.
Advantageously, the application takes place such that the applied
layer has a portion of gaps or respectively depot zones of 10-60%
and in particular 40% by volume, which has proven to be
particularly advantageous.
[0051] In order to combine the advantages of the elastic frame
created in this manner with the advantages of a clay court, the
second particle material is then applied and e.g. rolled in with
pressure. Alternatively or additionally, the second particle
material can be pressed into the depot zones with a vibrating
compactor.
[0052] It is preferred that the second particle material is applied
to the first material previously provided with the binder during
the setting time of the binder, i.e. the second particulate
material is applied to the not yet completely hardened first
particle material. A subset of the second particle material in the
depot zones is hereby bound to the particles of the first particle
material.
[0053] Furthermore, the above method advantageously permits the
setting of the respectively desired elasticity of the ground
covering through corresponding selection of the time between
application of the first particle material provided with the binder
and application of the second material. The longer this time span,
the smaller the subset of the second particulate material that is
bound with the first material, whereby the elasticity of the
covering is correspondingly higher.
[0054] The setting time for conventional polyurethane binders is
hereby approx. 4 hours so that the application of the second
particle material and thus a setting of the elasticity are easily
enabled.
[0055] The first particle material provided with the binder is
preferably applied in a thickness of approx. 15-50 mm and
preferably 25 mm. The second particle material is particularly
preferably applied in a quantity of approximately 0.8 to 4
kg/m.sup.2 and preferably 1.5 kg/m.sup.2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The invention is described below based on exemplary
embodiments. They show in:
[0057] FIG. 1 a schematic sectional view through a ground covering
according to the invention for sports areas according to a first
exemplary embodiment;
[0058] FIG. 2 a sectional view according to the exemplary
embodiment from FIG. 1 before application of a second particle
material;
[0059] FIG. 3 the exemplary embodiment according to FIG. 1 in the
case of a stopping movement of an athlete as well as
[0060] FIG. 4 the exemplary embodiment according to FIG. 1 in the
case of sliding movement of an athlete.
DETAILED DESCRIPTION
[0061] FIG. 1 shows an elastic slide ground covering for sports
areas and in particular for tennis courts according to a first
exemplary embodiment in a partial, schematic sectional view.
[0062] As shown, the covering has a play layer 4, which consists of
grains or respectively particles of a first mineral, doubly crushed
particle material 1 as well as a second particle material 3. In
order to provide a better overview, only a few of the shown grains
are labeled in the figures.
[0063] As can be seen in FIG. 1, the average particle size of the
second particle material 3 is considerably smaller than that of the
first particle material 1. According to the present example, the
particle size of the first particle material 1 is on average 8 mm
and the particle size of the second particle material 3 is on
average 0.75 mm.
[0064] For this reason, there are gaps or respectively "depot
zones" 5 in particular in the upper area of the play layer 4
between respectively neighboring particles of the first particle
material 1. Due to the fact that the first particle material 1 is
doubly crushed and thus mainly contains cubic particles,
particularly advantageous depot zones or respectively "anchoring
zones" are created. The second particle material 3 is arranged
predominantly in these depot zones 5, resulting in particularly
good play properties and an improved durability of the ground
covering, as explained below in relation to FIGS. 3 and 4.
[0065] The first particle material 1 consists in this case of clay
material predominantly crushed multiple times, which is bound by a
(single-component) binder 2, in this case PUR diphenylmethane
diisocyanate. The binder 2 forms a solid, water-impermeable and
film-like film by reaction with moisture on the boundary surfaces
under formation of carbon dioxide.
[0066] For production, the first particle material 1 is mixed
homogeneously with a compulsory mixer such that each individual
rock particle or respectively each particle of the first particle
material 1 is entirely enclosed in a thin film of binder 2, such as
for example indicated in FIG. 1. In order to avoid a tempering of
the binder 2 at temperatures greater than 20.degree. C., the binder
2 has a viscosity of approx. 4500 mPa*s. The portion of the PU
binder 2 in relation to the first particle material 1 is 7%.
[0067] The homogeneous mixture of the first particle material 1 and
binder 2 obtained in this manner is applied to an existing
subsurface (not shown) in a thickness of 25 mm and is stripped and
polished with a suitable device. The layer formed in this manner is
shown schematically in FIG. 2.
[0068] As can be seen in the figure, an open porous and elastic
granular structure provided with depot zones 5 is given, the
porosity or respectively size and number of depot zones 5 of which
depend directly on the particle size and particle shape as well as
on the stripping speed of the stripping movement.
[0069] In the case of an increase in the horizontal stripping
speed, the individual particles of the first particle material 1
encased in binder 2 are pulled further apart than for example in
the case of a slow stripping movement. The created granular
structure has in this case a 40% share of depot zones by volume,
i.e. it consists of 60% rock particles or respectively particles
and 40% depot zones, which are filled with the second particle
material 2 in the finished layer 1.
[0070] Since, in this case, each individual particle of the
particle material 1 is encased in an elastic and water-impermeable
plastic film, water absorption cannot take place since the granular
structure has no capillary function. Furthermore, a large pore
percentage is given and furthermore a plurality of smaller
connection and adhesion zones are given through the crushed shaped
so that the applied particle material 1 cannot freeze up. However,
a certain elasticity or respectively surface elasticity is given.
Moreover, the layer 4 has a permanently high water
permeability.
[0071] The granular structure formed in this manner already has
important positive characteristics of a hard court, such as e.g.
consistent ball bounce, low maintenance and no need for
watering.
[0072] In order to combine the above advantages with those of a
clay court, the second particle material 3, which consists here of
an elastic-synthetic granulate made of styrene butadiene rubber
(SBR), is applied during the setting time of the binder 2, i.e.
within 4 hours. This is applied, distributed and/or rolled in with
pressure to the granular structure with a small excess.
Alternatively, it can be pressed into the depot zones with a
vibrating compactor. As already mentioned, the finished covering
with play layer 4 is shown in FIG. 1.
[0073] As shown there, a small excess of approx. 20% of the second
particle material 3 remains on the surface, while approx. 80% is
pressed into the depot zones. Of this 80% of the second particle
material 3, a subset of approx. 5% is joined, i.e. combined
together, with the first particle material 1 through the not yet
completely hardened binder 2.
[0074] Since the second particle material 3 is rolled or
respectively pressed into the depot zones 5 under pressure, it
returns in an increased manner to the surface after the rolling
procedure due to the elasticity of the individual particles in the
area of the depot zones 5. If pressure is now exerted on the layer
4, the elastic granulate particles of the second particle material
3 press together so that an elastic effect is achieved.
[0075] The depot zones 5 simultaneously effectuate a controlled
braking depending on the placement of the foot of the player. FIG.
3 shows the exemplary embodiment according to FIG. 1 in the case of
a stopping movement of a player. The shoe 6 of the player is shown
here in the case of a sudden braking. As can be seen in FIG. 3, a
fairly large "chock," which presses against the edges of the depot
zones 5 with a high pressure, is formed by the aforementioned
excess of the second particle material 3 and thus a controlled
braking is supported. A sliding movement of the shoe 6, as shown in
FIG. 4, is simultaneously supported in that only a low surface
pressure is given here and the existing excess ensures a controlled
sliding.
[0076] Since high propulsive forces occur on the first particle
material 1, particularly in the uppermost rock layer, caused by the
high vertical propulsive forces during braking or respectively
sliding, the depot zones 5 serve as an additional anchor for the
individual coarse particles against vertical displacement or
respectively breakaway additionally due to the high quantity of
pressed-in second particle material 3, since the second particle
material 3 introduced into the depot zones 5 has approx. 1.5 times
the volume of a particle of the first particle material 1.
[0077] The elastic slide ground covering with play layer 4 provided
in this manner thus combines the advantages of a hard court with
those of a clay court. In particular, the covering requires no
watering and can thus be installed on any existing subsurface
inside (e.g. in tennis centers) as well as outside year-round in
all climate zones with little maintenance. The invention was
explained above based on exemplary embodiments. However, the
invention is not limited to the above embodiments. In particular,
the explained exemplary embodiments permit numerous changes or
updates. For example, it is conceivable that [0078] the first
particle material 1 has, alternatively or in addition to a clay
material, granite, basalt, quartz or slate chippings, [0079] the
second particle material 3 is a mineral, [0080] the second particle
material 3 comprises, alternatively or additionally, an elastic
granulate made of ethylene propylene diene rubber (EPDM=ethylene
propylene diene monomer) and/or [0081] the application of the
second particle material 3 only takes place after complete
hardening of the binder 2.
* * * * *